1. Field of the Invention
The present invention relates generally to a threaded member, and more particularly to a threaded member, which is capable of detecting the axial extension force/tension applied to the threaded member when an article is tightened with the threaded member.
2. Description of the Related Art
It is well known that threaded members such as bolts, screws and nuts are widely used in various fields for fixedly connecting two (or more) articles with each other, (such as mechanical equipments, sophisticated instruments, construction engineering, etc.) The threaded members can be easily screwed and tightened to fixedly connect the articles with each other. However, in the case that the threaded members are applied to those high-science/technology instruments requiring high precision or applied to construction engineering requiring high security, in addition to fixed connection between the connected sections, the threaded members are further required to tighten the connected sections of the articles by precise tightening force. In case the threaded members are under-tightened or over-tightened, not only the design requirement cannot be satisfied, but also the use effect and security of the tightened articles (such as the mechanical equipments) will be affected. Therefore, in order to find the tightening force/tightening torque applied to the threaded members for tightening the articles, conventionally, a sensor is disposed on the bolt or the screw. When the articles are tightened with the bolt/screw, the sensor can detect the deformation of the bolt to achieve the tightening force/tightening torque applied to the bolt. In this case, an operator can control the tightening force applied to the bolt to meet the requirement of high precision so as to ensure security.
The above technique is able to detect the deformation of the threaded member to find the tightening force applied to the threaded member according to the relationship between the deformation and the tightening force. The present invention provides another detection technique with different structural design for more clearly and precisely detecting the stress change so as to more precisely find the tightening extent of the threaded member and enhance the precision of the tightening extent of the threaded member.